Patellar Bone Research Articles

Changes in donor site after two variants of patellar tendon graft harvest

Background. The patellar tendon is often used as ACL graft. Identifying of factors that improve donor site healing may improve the outcomes.Aim. Study changes in the patellar tendon after two variants of graft harvest techniques and determine what features contribute to better donor site healing.Methods. The morphology of the patellar tendon was studied after two variants of graft harvest techniques with early rehab protocol. The retrospective group included 30 patients with no patellar tendon and bone defects closure. The prospective group included 30 patients with full-layer patellar tendon suture and bone defects closure. The Insall-Salvati ratio after surgery was measured on an X-ray in both groups. MRI study before surgery and 12 months after and CT 1 day and 6 months after surgery was performed in prospective group. The sizes of patellar tendon and conditions of bone defects were studied. Results. Patella position was physiological and did not differ between the groups (1.11 ± 0.13 - in group 1 and 1.12 ± 0.15 - in group 2, p = 0.955). In the prospective group after 12 months the patellar tendon length was shorter by 3.1% (-1.4 ± 2.4 mm, p = 0.003); the ligament width in the upper and middle thirds slightly increased (0.3±2.4 mm, p=0.502 and 0.5±2.1, p=0.205), and in the lower third it was 2.7% greater (0.7±1.7 mm, p=0.034); the ligament thickness increased by 55% (2.4±1.6 mm, p=0.001). All patients in group 1 had persistent bone and tendon defects. In group 2 the bone defects healed 6 months after, the ligament restored its shape and size, approaching the preoperative values 12 months after the surgery.Conclusions. Full-layer suture of the patellar tendon, autoplasty of bone defects and early mobilization ensure healing of bone defects and restoration of the integrity, shape and size of the ligament.

Patellar morphology is different in patellofemoral instability: An MRI comparative case-control study

PurposeAlthough patellofemoral instability (PFI) affects both femoral and patellar compartments, literature provided little attention for the patellar morphology contribution on PFI. This study evaluates the patellar morphology patterns on MRI to establish their contribution in PFI. MethodsThis study retrospectively analyzes patellar MRI and X-ray measurements performed between 2018 and 2022. 50 knees with recurrent patellar dislocation were matched with 50 matched knees of ACL-reconstruction candidates with no history of patellar dislocation based on age and gender. Caton-Deschamps’ index, Wiberg’s patellar morphotype, Dejour’s trochlear dysplasia classification, sagittal patellofemoral engagement index and additional patellar cartilage and bone parameters and their relative ratio measurements were assessed in both groups. ResultsStudy patients present differences in patellar morphology; a wider lateral facet (p = 0,019) and a narrower medial facet compared to the control group (p < 0,001). The subchondral patellar crest is medialized compared to the control group (p < 0,001). The cartilaginous crest measurements of the patella were not significantly different in both groups yet PFI group presents a wider Wiberg angle (p < 0,001), thus a flatter patella, compared to the control group. ConclusionThe patella in PFI patients presents a larger lateral facet, a narrower medial facet, a flatter surface and a medialized patellar crest compared with the control group. In PFI, a rather medial patellar crest might predispose towards a greater patellar tilt and destabilize the already compromised patellar-trochlear groove congruence. PFI is a multifactorial disease and both trochlea and patella play a role in its manifestation, thus, literature should address patellar morphotype contribution in patellofemoral instability.Level of Evidence: Level III.

Does Resurfacing the Patella Increase the Risk of Extensor Mechanism Injury within the First 2 Years after Total Knee Arthroplasty?

Extensor mechanism injury (EMI) following total knee arthroplasty (TKA) is a potentially catastrophic complication and may lead to significant morbidity or need for revision reconstructive procedures. Patellar resurfacing (PR), while commonly performed during TKA, reduces overall patella bone stock and may increase the risk of EMI after TKA. The purpose of this study was to assess if PR in elderly patients raises the risk for subsequent EMI.The American Joint Replacement Registry (AJRR) was queried to identify Medicare patients ≥65 years old undergoing primary elective TKA for osteoarthritis between January 2012 and March 2020. Patient age, sex, and Charlson Comorbidity Index (CCI) were collected. Records were subsequently merged with Medicare claims records and evaluated for the occurrence of patella fracture, quadriceps tendon rupture, or patellar tendon rupture based on International Classification of Diseases 9 and 10 (ICD 9/10) diagnosis codes within 2 years of TKA. Patients were stratified based on whether PR occurred or not (NR). Logistic regression was used to determine the association between PR and EMI.A total of 453,828 TKA were eligible for inclusion and 428,644 (94.45%) underwent PR. The incidence of PR decreased from 96.06% in 2012 to 92.35% in 2022 (p < 0.001). Patients undergoing PR were more often female (60.93 vs. 58.50%, p < 0.001) and had a lower mean CCI (3.09 [1.10] vs. 3.16 [1.20], p < 0.001). Odds for EMI did not differ based on whether PR was performed (odds ratio [OR]: 0.85, 95% confidence interval [CI]: 0.65-1.11, p = 0.2246). Increasing age (OR: 1.06, 95% CI: 1.05-1.07, p < 0.0001]) and CCI (OR: 1.06, 95% CI: 0.95-1.19, p = 0.0009) were associated with EMI.PR is commonly performed during TKA in the United States and was not found to increase odds for EMI within 2 years of TKA in patients ≥65 years old. Increased age and medical comorbidity were associated with higher odds for subsequent EMI.

Patellar bone defect grafting does not reduce anterior knee pain after bone-patellar tendon-bone anterior cruciate ligament reconstruction.

Donor site morbidity is the main drawback to using bone-patellar tendon-bone (BPTB) as a graft in anterior cruciate ligament (ACL) reconstruction. The objective of the study was to determine whether refilling the patellar bone defect after BPTB harvesting with autograft bone decreased kneeling pain to a greater degree when compared with a group in which bone defect is left unaddressed. This is a randomised single-blinded controlled study. Forty patients were randomised into two groups; group 1: Patellar bone defect filled with autologous bone; group 2: Bone defect left undressed. Pain was measured by means of pressure algometry (PA). Functional outcomes were measured with the Kujala and Victorian Institute of Sport Assessment-Patella (VISA-P) score. Magnetic resonance imaging (MRI) was done to measure bone buildup between groups at the 1-year follow-up. No differences were observed in the different algometry measurements and the scores were assessed at 3, 6 and 12 months postoperatively. The ratio of void filled remained consistently higher (p = 0.003) in group 1 when compared to group 2. Although refilling the lower pole of the patella with autologous bone from the harvested BPTB autograft loads the bone defect, it does not reduce pain at the donor site 1 year after surgery. Therapeutic study level 1.

No Clinical Advantage of Harvesting a Patellar Bone Block Compared With All Soft-Tissue Graft in Primary Quadriceps Tendon Anterior Cruciate Ligament Reconstruction

PurposeTo compare patient-reported outcomes measurements (PROMs) and subsequent surgical interventions in patients treated with anterior cruciate ligament reconstruction (ACLR) using either quadriceps tendon autograft with a patellar bone block (bQT) or soft tissue only (sQT). MethodsAll ACLRs performed between 01.2010 and 03.2022 were prospectively followed for 24 months and retrospectively evaluated. All primary ACLRs with full 24 months of follow-up data, without any previous surgery or any additional ligamentous interventions, were matched for major ACL risk factors, including gender, age, Tegner activity level (TAL), pivoting sports, and concomitant injuries. PROMs (Lysholm score, Visual Analog Scale (VAS) for pain, and TAL) and subsequent surgical interventions were registered after 6, 12, and 24 months postoperative. Binary logistic regression was used to assess the influence of graft type, age, preinjury TAL, gender, pivoting sports and concomitant interventions on the need to undergo subsequent surgery. ResultsAfter matching, 246 patients were included in the final analysis. Both groups did not differ regarding any preoperative patient demographics or intraoperative details. At final follow-up, no significant difference in mean Lysholm score (sQT: 90.8±10.6, bQT: 91.8±10.6, p= .46), median TAL (sQT: 6 [1-10], bQT: 6 [1-10], p= .53) and VAS for pain (sQT: 0.7±1.1, bQT: 0.7±1.2, p= .70) was reported between both groups. 70.3% (sQT-A: 70.7%, bQT: 69.9%, p= .89) of patients returned to or exceeded their preinjury activity level. In terms of revision ACLR, there was no statistically significant difference between bQT (3.3%) and sQT (4.1%). Similarly, no difference was observed in contralateral ACLR (bQT: 7.3% sQT: 11.4%). Regression analysis indicated that none of the studied factors, including the use of a patellar bone block, influenced subsequent surgery, revision ACLR, or contralateral ACLR. ConclusionHarvesting an additional patellar bone block in quadriceps tendon ACL reconstruction does not seem to impact postoperative patient-reported outcomes, ACL revision- or contralateral ACL reconstruction rates. Level of EvidenceLevel 3 – Cohort Study

Femoral tunnel length does not impact outcomes following ACL reconstruction using a single-bundle quadriceps tendon autograft: A systematic review.

To determine whether femoral tunnel length (FTL) affects clinical or functional outcomes following primary Anterior cruciate ligament reconstruction (ACLR) with single-bundle quadriceps tendon autograft, both with and without a patellar bone block. An electronic search of MEDLINE, EMBASE, and Cochrane databases was carried out via OVID. Data pertaining to study characteristics, patient demographics, surgical techniques, femoral tunnel length, and subjective/objective clinical outcomes was abstracted. Studies were stratified into two groups based on FTL; a short femoral tunnel (S-FT) group of ≤25 mm, and a long femoral tunnel (L-FT) group of >25 mm. There was a high degree of heterogeneity between studies, prohibiting meta-analysis. Seven studies comprising 368 total patients with a mean age of 30.3 years (range: 23.4-34 years) were included for analysis. The S-FT group included 126 patients and the L-FT group 242 patients. Both groups demonstrated statistically significant postoperative improvements across both subjective and objective clinical and functional outcomes. Average complication rates were 11.9% (range: 0%-29%) in the S-FT group and 4.5% (range: 1%-14%) in the L-FT group. Ranges of re-rupture rates were 0%-2% and 0%-3% for the S-FT and L-FT groups, respectively (n.s.). Both S-FT and L-FT groups demonstrated comparable postoperative outcomes following primary ACLR with single bundle quadriceps tendon autograft. There were slightly superior, although non-significant, outcomes reported with short femoral tunnel length, however, this may have been confounded by the variation in surgical technique used. IV.

Racialized experience, biomarkers of lead exposure, and later-life cognition: a mediation analysis.

We evaluated the role of the neurotoxicant lead (Pb) in mediating racial disparities in later-life cognition in 1,085 non-Hispanic Black and 2,839 non-Hispanic white participants in NHANES (1999-2002, 2011-2014) 60+ years of age. We operationalized Black race as a marker for the experience of racialization and exposure to systemic racism. We estimated patella bone Pb via predictive models using blood Pb and demographics. Concurrent cognition (processing speed, sustained attention, working memory) was measured by the Digit Symbol Substitution Test (DSST) and a global measure combining four cognitive tests. To obtain the portion mediated, we used regression coefficients (race on Pb * Pb on cognitive score)/(race on cognitive score), adjusting for age, NHANES cycle, and sample weights. Other confounder adjustment (education, poverty income ratio, smoking) was limited to the mediator-outcome (i.e., Pb-cognition) pathway because these factors do not lie upstream of race and so cannot confound associations with race. Pb was estimated to mediate 0.6% of the association between race and global cognition, and 4% of the DSST. Our results suggest that later-life cognitive health disparities may be impacted by avoidable lead exposure driven by environmental injustice, noting that a large proportion of the pathway of systemic racism harming cognition remains.

A modified anterior cruciate ligament reconstruction with BTB autograft

Background. Central third of the patellar tendon is a well know graft for anterior cruciate ligament (ACL) reconstruction. However, it’s usage can be difficult in case of long patella tendon, which causes graft length discrepancy. The aim of this article is to evaluate the results of arthroscopic anterior cruciate ligament reconstruction with a help of original method of bone patella tendon bone graft preparation. Methods. 26 males operated for ACL tear have been included in the study. On the preoperative MRI scans the approximate length of ACL, tibial tunnel, patella tendon length and tibial bone plug length have been measured. The technique of tibial bone plug cut was optimized based on preoperative MRI assessment. Results. In all cases, MRI-based assessments were consistent with intraoperative measurements, hence there was possible to avoid graft length discrepancy. In a period of 12 weeks the average score on the step-and-holds test was 23.8±1.1, the single-leg squat test was 6.7±0.9 and the Y-balance test was 83.2±1.4. The average IKDS score was 64.9±5.7. Conclusion. The proposed method is appropriate for anterior cruciate ligament reconstruction in patients with long patella tendon.

Poster 241: Comparison of Short-Term Clinical Outcomes of Medial Patellofemoral Ligament Reconstruction Using Superficial Quadriceps Tendon and Using Hamstring Tendon in Patella Instability

Objectives: Medial patellofemoral ligament reconstruction (MPFLR) is widely acknowledged as a therapeutic approach for patella instability. While hamstring autografts are widely used in MPFLR, there are concerns regarding complications associated with the patella bone tunnel and fixation hardware, such as the endobutton. As an alternative, the superficial quadriceps (SQ) tendon has also been used presently. To date, few studies have evaluated the comparison of clinical outcomes between the grafts. The purpose of the present study is to compare the short-term clinical outcomes of MPFLR using superficial quadriceps tendon and using hamstring tendon. Methods: All patients who had undergone MPFLR for patella instability between 2017 and 2020 and were able to follow up for &gt;2 years were retrospectively evaluated. For autograft of MPFLR, hamstring was inserted to the patellar bone tunnel formed at superomedial corner of the patella or through the whole patella (ST group), while the center third of the superficial layer of the quadriceps tendon graft was harvested and turned medially leaving its attachment to the patella intact (SQ group). Both grafts were fixed at Schottle’s point with an initial tension of 10-20 N and 30° of knee flexion. Preoperative assessment included the range of knee motion (ROM), and radiographic features such as tibial tubercle–trochlear groove (TT-TG) distance, patellar tilt, and sulcus angle. The Kujala score, Tegner activity score, Lysholm score, ROM, and patellar tilt were assessed at one year postoperatively. Failure was defined by a postoperative patellar dislocation, surgical revision for recurrent patellar instability or any complication. Paired t test and 2-way repeated measure analysis of variance followed by multiple comparison using the Bonferroni test was carried out for statistical analysis, and statistical differences were considered significant for values of p &lt; 0.05. Results: Among 70 MPFL reconstructions, 65 patients (92.9%, 24 males and 41 females) were able to follow-up. The mean follow-up period was 3.1 years (2 to 5 years). There were 22 patients in the ST group and 43 patients in the SQ group. There was no difference in preoperative TT-TG distance (ST group: 14.1 mm ± 4.6 mm, SQ group: 16.2 mm ± 3.1 mm) and sulcus angle (ST group: 143.1° ± 12.4°, SQ group: 139.6° ± 8.9°). Postoperatively, there was no significant difference in Tegner activity score (ST group: 5.5 points ± 2.2 points, SQ group: 5.8 points ± 2.2 points), but the SQ group showed significantly high score in Lysholm score (ST group: 88.7 points ± 12.5 points, SQ group: 95.9 points ± 5.9 points; p &lt; 0.01) and Kujala score (ST group: 91.8 points ± 4.1 points, SQ group: 94.9 points ± 5.1 points; p &lt; 0.01). ROM improved postoperatively, but there was no significance between the 2 groups. The Tilting angle (preoperative; ST group: 24.8° ± 12.0°, SQ group: 20.2° ± 8.3°) improved significantly (postoperatively; ST group: 10.9° ± 4.8°, SQ group: 11.5 ± 4.5°) (p &lt; 0.01). There were 3 failures (13.6%) in the ST group with 2 patellar fractures and 1 postoperative patellar dislocation requiring additional surgery. Conclusions: Both groups had good short-term results, but postoperative Lysholm score and Kujala score were higher in the SQ group. Postoperative improvement in tilting angle reveals that both grafts contribute to restoring MPFL function. However, concerning failures that occurred in the ST group, SQ autograft may be safe and considerable for MPFLR. [Figure: see text][Figure: see text]

Poster 330: Graft Selection and Lateral Augmentation in Revision ACL Reconstruction: Experience of a Large Tertiary Academic Center

Objectives: Primary purpose of this study was to assess failure rates in revision ACL reconstruction and to determine the influence of graft selection and lateral augmentation procedures. A secondary purpose was to identify a subset of patients for whom reconstruction with allograft yields equivalent failure rates to autograft. Methods: This was a retrospective study at a tertiary academic medical center. The electronic medical record was queried for current procedural terminology codes for ACL reconstructions (29888) from June 2011 – October 2022. Data was reviewed to ensure that only revision ACL reconstructions were included. Demographic information including age, gender, and BMI were obtained from the EMR query as well. Graft types used and lateral augmentation procedures performed were identified through manual review of operative notes. Failure rates were recorded based on documentation of ACL graft re-tear in the database. Results: Three-hundred thirty patients who underwent revision ACL reconstruction at our institution were included in the final analysis. Patients were 30.2% female with a mean age of 31.9 years (SD 10.5). Mean follow up was 21.7 months (SD 25.8). Overall re-tear rate at final follow up was 6.7%. Lateral augmentation procedures were performed in 42.1% of patients (48.2% anterolateral ligament reconstruction [ALL], 51.8% lateral extraarticular tenodesis [LET]). The most common graft types were bone patella bone (BTB) allograft (40.3%) and BTB autograft (36.1%). Other graft types included quadriceps tendon autograft (6.4%), hamstring tendon allograft (5.2%), hamstring tendon autograft (4.5%), tibialis anterior allograft (4.2%), Graftlink allograft (1.5%), quadriceps tendon allograft (1.5%), and Achilles tendon allograft (0.3%). Age, gender, and BMI were not significantly different between patients who retore their ACL graft vs. those who did not (p&gt; .05). Patients who underwent a LET procedure had significantly lower failure rates (0%) than those who underwent an ALL reconstruction (10.4%) or no lateral augmentation procedure (7.9%), (p=.029). Failure rates for the three most common grafts used are shown in Figure 1. The rate of re-tear was significantly higher in patients who underwent reconstruction with allograft as compared to autograft (10.3% vs. 2.6%, p=.007). When only patients above 40 years of age were analyzed (n=67), the rate of re-tear was not significantly different in patients who underwent reconstruction with allograft as compared to autograft (8.8% vs. 10.0%, p=.999). There was a higher proportion of patients over 40 with allograft who underwent LET (22.8% vs. 10.0%), but this was not statistically significant (p=.675). Among patients under 40 who underwent reconstruction with allograft, a lower proportion of patients who had a re-tear underwent LET than those who did not re-tear (0% vs. 16.3%), but this was not statistically significant (p=.210). Conclusions: Overall re-tear rates were higher in patients who underwent revision ACL reconstruction with allograft. However, in older patients who may be less active, re-tear rates were comparable for allograft and autograft. Additionally, patients who underwent lateral extraarticular tenodesis had lower re-tear rates. Careful consideration of patient demographics and clinical characteristics is necessary for graft selection and indication for lateral augmentation in revision ACL reconstruction.

Improving prediction of linear regression models by integrating external information from heterogeneous populations: James-Stein estimators.

We consider the setting where (1) an internal study builds a linear regression model for prediction based on individual-level data, (2) some external studies have fitted similar linear regression models that use only subsets of the covariates and provide coefficient estimates for the reduced models without individual-level data, and (3) there is heterogeneity across these study populations. The goal is to integrate the external model summary information into fitting the internal model to improve prediction accuracy. We adapt the James-Stein shrinkage method to propose estimators that are no worse and are oftentimes better in the prediction mean squared error after information integration, regardless of the degree of study population heterogeneity. We conduct comprehensive simulation studies to investigate the numerical performance of the proposed estimators. We also apply the method to enhance a prediction model for patella bone lead level in terms of blood lead level and other covariates by integrating summary information from published literature.

Ellipsoidal patellar bone tunnel fixation with Toggleloc suspension system for medial patellofemoral ligament reconstruction: A 5 years follow-up.

This study aimed to evaluate the clinical and radiological features of the patella fixation technique using Toggleloc suspension system in a single ellipsoidal blind patellar tunnel during medial patellofemoral ligament (MPFL) reconstruction. This study included 52 patients (25 men, 27 women) who underwent MPFL reconstruction using a semitendinosus tendon graft. The graft was fixed to the ellipsoidal single blind tunnel opened on the medial side of the patella with an endobutton and was fixed to the femoral tunnel by using bioabsorbable screw. Clinical scores (Kujala score, Lysholm score, Tegner activity score and the visual analog scale [VAS] score) were evaluated preoperatively and at the end-follow up. Preoperative and postoperative radiological measurements (trochlea depth, sulcus angle, patellar height, patellar congruence angle, patellar tilt angle and lateral patellofemoral angle) were evaluated with X-ray (Merchant X-ray, anteroposterior and lateral radiography) and computed tomography (CT) of the knee. Postoperative patellar redislocation or subluxation was not observed in any patient. Patellar congruence angle, patellar tilt angle and lateral patellofemoral angle mean values were found to return to normal values in the postoperative period and the results were statistically significant. Also statistically significant improvement in all clinical scores postoperatively. According to the Insall-Salvati index (ISI) and Caton-Deschamps index (CDI) on lateral radiography of the knee at 30° flexion, patellar height decreased in the postoperative period statistically significant. The CDI was above 1.3 in 17 (%32) of our patients. Thirteen of these values decreased to normal values. No radiological progression of patellofemoral osteoarthritis was observed in all patients at the final follow-up evaluation. In cases of patellofemoral instability, fixation of the tendon graft in blind ellipsoid tunnel using the Toggleloc suspension system provides satisfactory patellar graft fixation strength, significant functional improvement and a low failure rate.

Analysis of knee-bending motion through three-dimensional scanning for advanced brace design

Knee braces have been increasing in popularity as a means to support joint stability and promote the healing process. In order to enhance the fit, comfort, and design of knee braces, this study investigates knee shape deformations across four knee-bending angles from 0° to 90°. Using three-dimensional (3D) scanning technology, the knee contours of 50 Asian males aged between 22 and 33 were examined. The reliability of the 3D measurements was validated through comparisons with tape measurements on the actual body. The analysis revealed a stretch of the skin covering the patella bone with a notable vertical strain of 19% and horizontal stretching of 7%. The circumference along the muscle belly at the thigh (15 cm above the center of the patella) and at the calf (7.5 cm below the center of the patella) showed no significant changes with different bending angles, and can be used as an indicator for sizing of knee braces. However, at the patella bone level, the bending of the knee from 0° to 90° increased the knee circumference by 6.4%. The results from sectional analysis showed the asymmetry and the lateral shifting of the knee joint during bending. The findings offer guidelines for the design and optimization of knee braces to address knee deformations and individual body shape variations.

Combined Medial Quadriceps Tendon-Femoral Ligament and Medial Patellofemoral Ligament Reconstruction for Revision Patellofemoral Soft-Tissue Stabilization

Patients with recurrent patellofemoral instability in whom prior medial patellofemoral ligament (MPFL) reconstruction fails present unique challenges for revision soft-tissue stabilization owing to scar tissue formation, limited patellar bone stock for anchor placement, and increased risk of patellar fracture. We describe a technique for revision patellofemoral soft-tissue stabilization that combines MPFL and medial quadriceps tendon–femoral ligament reconstruction techniques through combined fixation to the patella with 1 suture anchor and soft-tissue fixation to the quadriceps tendon. The proposed technique maximizes restoration of resistance to lateral translation by attempting to re-create the native MPFL attachment and minimizes patellar fracture risk in the setting of poor bone stock through the use of a single 1.8-mm all-suture suture anchor rather than bone tunnels or multiple anchor placement for bony fixation.

Clinical and Computational Evaluation of an Anatomic Patellar Component

BackgroundAnatomic patellar components for total knee arthroplasty (TKA) have demonstrated favorable in vivo kinematics. A novel failure mechanism in TKA patients with an anatomic patellar component was observed prompting an investigation to identify patient- and implant-related factors associated with suboptimal performance. MethodsA retrospective evaluation was performed comparing 100 TKA patients with an anatomic patellar component to 100 gender-, age-, and body mass index–matched patients with a medialized dome component. All surgeries were performed with the same posterior-stabilized TKA system with minimum of 1-year follow-up. Several radiographic parameters were assessed. A separate computational evaluation was performed using finite-element analysis, comparing bone strain energy density through the patella bone remnant. ResultsPatients with an anatomic patellar component had significantly higher rates of anterior knee pain (18 versus 2%, P < .001), chronic effusions (18 versus 2%, P < .001), and superior patellar pole fragmentation (36 versus 13%, P < .001) compared to those with a dome component. Radiographically, the anatomic group demonstrated more lateral patellar subluxation (2.3 versus 1.1 mm, P < .001) and lateral tilt (5.4 versus 4.0 mm, P = .013). Furthermore, there were more revisions in the anatomic group (7 versus 3, P = .331). On computational evaluation, all simulations demonstrated increased bone strain energy density at the superior patellar pole with the anatomic patella. Resection thickness <13 mm resulted in over 2-fold higher strain energy density, and negative resection angle of 7° resulted in 6-fold higher superior pole strain energy. ConclusionsPatients with an anatomic patellar component showed higher rates of anterior knee pain, chronic effusion, and superior pole fragmentation compared to patients with a dome patella, with higher superior patellar pole strain energy confirmed on computational evaluation. Avoiding higher resection angles and excessive patellar resection may improve the performance and survivorship of the anatomic patella.

Association between quadriceps fat pad edema and patellofemoral osteoarthritis: a quantitative Q-Dixon-based magnetic resonance imaging (MRI) analysis.

Anterior knee pain (AKP) is a common symptom of patellofemoral osteoarthritis (PFOA). There is limited prospective evidence supporting the relationships between patellofemoral maltracking parameters, AKP, and PFOA. Thus, this prospective cross-sectional study aimed to determine the association between quadriceps fat pad (QFP) edema and patellofemoral maltracking in patients with chronic AKP and to evaluate the feasibility and diagnostic performance of a PFOA assessment using fat fraction (FF) and T2* based on Q-Dixon. This was a cross-sectional study with prospective data collection. Patients with chronic AKP were recruited from an orthopedic outpatient magnetic resonance imaging (MRI) waiting room at Shanghai Tongren Hospital between November 1, 2022, and April, 30, 2023. Exclusion criteria included age of <18 years, knee trauma, major internal derangement, prior surgery/arthroscopy, pre-existing joint diseases, and contraindications to MRI. MRI was performed using a 3.0-T instrument, and patellofemoral maltracking parameters were measured. Patellofemoral feature-relevant items, including patellar cartilage defects, patellar bone marrow lesions (BMLs), patellar osteophytes, anterior femoral osteophytes, Hoffa synovitis, and synovitis-effusion, from the semi-quantitative MRI Osteoarthritis Knee Score (MOAKS) were measured. The Anterior Knee Pain Scale (AKPS) was used to assess pain and function. FF/T2* measurement differences between groups and their associations with maltracking metrics, osteoarthritis grading based on the Iwano grading system, MOAKS, and AKPS, were investigated. Based on Iwano grading, the participants were categorized as having no-PFOA (n=40), mild PFOA (n=40), and advanced PFOA (n=40). Chi-squared and one-way analysis of variance were used to assess potential differences between the groups. Spearman's correlation test was used to analyze the correlation between the morphological parameters, AKPS, Iwano grade, MOAKS, and MRI quantitative values. Receiver operating characteristic (ROC) curves assessed the area under the curve (AUC), sensitivity, and specificity of quantitative values for distinguishing PFOA from no-PFOA. Among the 120 included patients, those in the mild (86.2±8.5) and advanced (83.9±9.5) PFOA groups had significantly lower AKPS scores than those in the no-PFOA group (88.8±7.3) (P=0.03). The mean FF and T2* values of the QFP were significantly higher in the no-PFOA group than those in the mild and advanced PFOA groups (P<0.001 for FF and P=0.02 for T2*). Quantitative data on the QFP and patellofemoral maltracking parameters showed no association. FF (r=-0.686, P<0.001) and T2* (r=-0.314, P=0.008) showed a negative correlation with the Iwano grade. The AUCs for PFOA diagnosis were 0.906 [95% confidence interval (CI), 0.853-0.960] (FF) and 0.744 (95% CI, 0.657-0.831) (T2*). QFP FF and T2* were not associated with patellofemoral maltracking parameters but with increased PFOA in patients with AKP, suggesting that QFP abnormalities play a role in PFOA. Therefore, a quantitative QFP assessment (FF and T2*) based on Q-Dixon technology could be a convenient and reliable new imaging biomarker for PFOA severity during clinical diagnosis, treatment, and follow-up.

A comprehensive MRI investigation to identify potential biomarkers of Osgood Schlatter disease in adolescents: A cross sectional study comparing Osgood Schlatter disease with controls.

Osgood-Schlatter disease (OSD) is the most common knee pain complaintamong adolescents playing sports. Despite this, there remains controversy over the pathophysiology and whether specific anatomical characteristics are associated with OSD. This study aimed to systematically and comprehensively characterize adolescents with OSD using magnetic resonance imaging (MRI) compared to pain-free controls, including both tissue abnormalities that may be associated with OSD, as well as anatomical characteristics. A secondary objective was to identify potential imaging biomarkers associated with pain. Cross-sectional study. Adolescents with OSD and controls were recruited from 2020 to 2022. Following a clinical exam, demographics, pain, sports participation, and Tanner stage were collected. Knee MRI was conducted on the participants' most symptomatic knee (OSD) or the dominant leg (controls). Sixty-seven adolescents (46 with OSD and 30 controls) were included. 80% of participants with OSD had at least one tissue alteration compared to 54% of controls. Compared to controls, OSD had 36.3 (95%CI 4.5 to 289.7) higher odds of bony oedema at the tibial tuberosity, and 32.7 (95%CI 4.1 to 260.6) and 5.3 (95%CI 0.6 to 46.2) higher odds of bony oedema at the tibial epiphysis and metaphysis respectively. Participants with OSD also had higher odds of fluid/oedema at the patellar tendon (12.3 95%CI 3.3 to 46.6), and superficial infrapatellar bursitis (7.2). Participants with OSD had a more proximal tendon attachment (mean tibial attachment portion difference, -0.05, 95% CI: -0.1 to 0.0, p = 0.02), tendon thickness (proximal mean difference, -0.09, 95% CI: -0.4 to 0.2, p = 0.04; distal mean difference, -0.6, 95% CI: -0.9 to -0.2, p = 0.01). Those with bony/tendon oedema had 1.8 points (95% CI: 0.3 to 3.2) higher pain on palpation than those without (t = -2.5, df = 26.6, p = 0.019), but there was no difference between these groups in a functional single leg pain provocation. Adolescents with OSD present with tissue and structural abnormalities on MRI that differed from age-matched controls. The majority had findings in the patellar tendon and bone, which often co-occurred. However, a small proportion of OSD also presents without alterations. It appears these findings may be associated with clinical OSD-related pain on palpation of the tibial tuberosity. Our highlight the pathophysiology on imaging, which has implications for understanding the mechanism and treatment of OSD.

The Influence of Tunnel Parameters and Graft Inclination Angle on Clinical and Radiological Outcome at Long-term Follow-up after Arthroscopic Anterior Cruciate Ligament Reconstruction.

Objective To study the influence of various tunnel parameters and graft inclination angle (GIA) on the clinical and radiological outcome after anterior cruciate ligament reconstruction (ACLR) at long-term follow-up. Methods In this retrospective study, 80 patients with isolated anterior cruciate ligament (ACL) injury treated by single bundle ACLR using bone patellar tendon bone (BPTB) and hamstring (HT) autografts were evaluated clinically and radiologically at their long-term follow-up. The study population were divided into two groups based on ideal and nonideal tunnel parameters as well as ideal and nonideal GIA. The various tunnel parameters and GIA were interpreted with clinical and radiological outcome at long-term follow-up. Results Eighty patients, 36 (45%) using BPTB and 44 (55%) using HT autografts, were available to complete the study. Patients with ideal coronal tibial tunnel angle (CTTA) and coronal femoral tunnel angle (CFTA) show superior clinical outcome (pivot shift test) than nonideal CTTA and CFTA, which was found to be statistically significant ( p -value < 0.038 and 0.024, respectively). Similarly, patients with ideal coronal tibial tunnel position (CTTP) show superior clinical outcome (International Knee Documentation Committee - IKDC objective) over nonideal CTTP ( p -value < 0.017). All other tunnel parameters and GIA were not found to have influence on clinical outcome. None of the tunnel parameters have influenced osteoarthritis (OA) change. There was no progression of OA change in the study population at long-term follow-up after ACLR. Conclusion Ideal coronal tunnel parameters produced a better clinical outcome at long-term follow-up after ACLR. There was no progression of OA change at long-term follow-up after isolated ACLR.

3D printed Nanohydroxyapatite/Polyamide 66 scaffolds with balanced mechanical property and osteogenic ability for bone repair

The biomaterial requirements for bone tissue repair are extremely strict. It not only requires the biomaterial to have good biocompatibility and biological activity, but also requires sufficient mechanical strength. Polyamide 66 (PA66) and nano-hydroxyapatite (n-HA) have been widely investigated in bone tissue engineering scaffold, however, its composites require further research. In this study, the 3D printing technology was utilized to fabricate personalized n-HA/PA66 bone tissue scaffold. The mechanical properties of n-HA/PA66 composite can be adjusted by configuring different raw material components and applying different porosity. It was found that 50 % porosity n-HA/PA66 composite scaffold showed a uniform porous structure and a compressive strength of 33.9 MPa. The composite scaffold also exhibited excellent biological properties while improving mechanical properties, in vitro cell tests indicated that the 3D printed n-HA/PA66 composite scaffold promoted differentiation of bone marrow mesenchymal stem cells (BMSCs) into osteoblasts. In in vivo animal model proved that the scaffold promoted endogenous bone regeneration in rabbit patellar bone defects, with newly formed bone volume of 20.9 % after two months of implantation. This research proposed a 3D printed polyamide/nano-hydroxyapatite composite with balanced mechanical property and osteogenic ability for customized bone tissue repair, and it has promising application prospects.

Management of Bone Loss in Revision Total Knee Arthroplasty: An International Consensus Symposium.

The evaluation, classification, and treatment of significant bone loss after total knee arthroplasty (TKA) continue to be a complex and debated topic in revision TKA (rTKA). Despite the introduction of new evidence and innovative technologies aimed at addressing the approach and care of severe bone loss in rTKA, there is no single document that systematically incorporates these newer surgical approaches. Therefore, a comprehensive review of the treatment of severe bone loss in rTKA is necessary. The Stavros Niarchos Foundation Complex Joint Reconstruction Center Hospital for Special Surgery, dedicated to clinical care and research primarily in revision hip and knee replacement, convened a Management of Bone Loss in Revision TKA symposium on June 24, 2022. At this meeting, the 42 international invited experts were divided into groups; each group was assigned to discuss questions related to 1 of the 4 topics: (1) assessing preoperative workup and imaging, anticipated bone loss, classification system, and implant surveillance; (2) achieving durable fixation in the setting of significant bone loss in revision TKA; (3) managing patellar bone loss and the extensor mechanism in cases of severe bone loss; and (4) considering the use of complex modular replacement systems: hinges, distal femoral, and proximal tibial replacements. Each group came to consensus, when possible, based on an extensive literature review and interactive discussion on their group topic. This document reviews each these 4 areas, the consensus of each group, and directions for future research.